Robot Cleaner Spin-Mop Path Overlap for Complete Floor Coverage

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Solution Overview

Problem

Robot cleaners that use spin-mops for mopping operations face challenges in maintaining a straight path due to varying frictional forces, leading to incomplete cleaning, especially near walls and obstacles, and conventional zigzag patterns often leave uncleaned regions.

Innovation Solution

A robot cleaner with two spin-mops that rotate in opposite directions and at different speeds, controlled by a controller to create a zigzag pattern, ensuring that one spin-mop's path overlaps the other's to cover the entire floor and prevent uncleaned regions, while also allowing for various travel motions and cleaning modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the robot cleaner uses spin-mops to travel autonomously, then cleaning capability is improved, but the robot cleaner cannot travel in a straight path due to varying frictional forces

Engineering Contradiction:
Improvecleaning capabilityVSAvoidtravel path accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The robot cleaner incorporates sensors to detect its position and orientation relative to the intended straight path. The control system continuously monitors the actual travel path and adjusts the rotation speeds of the spin-mops in real-time to compensate for deviations caused by varying frictional forces, enabling both straight path travel and effective cleaning

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the rotational speeds of the spin-mops based on detected friction variations and path deviations. By varying the rotation speeds adaptively rather than maintaining constant speeds, the robot can compensate for changing frictional conditions while maintaining both straight path accuracy and cleaning effectiveness

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If the robot cleaner uses conventional zigzag-pattern travel, then coverage area is improved, but uncleaned regions remain between the spin-mops

Engineering Contradiction:
Improvecoverage areaVSAvoidcleaning completeness
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The robot cleaner employs asymmetric positioning of the spin-mops relative to the body centerline, or asymmetric rotation speeds, creating an offset cleaning pattern. This asymmetry ensures that the cleaning paths of the two spin-mops overlap in a way that eliminates uncleaned regions while maintaining efficient zigzag traversal coverage

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The system introduces an additional control dimension by independently varying the rotation speeds of the spin-mops in addition to their rotational direction. This speed modulation creates overlapping cleaning trajectories that cover the central regions between the spin-mops, transforming the cleaning pattern from two separate paths to a continuous overlapping coverage area

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the robot cleaner sequentially rotates spin-mops to travel in S-shaped pattern, then straight path travel is improved, but travel speed and cleaning speed decrease

Engineering Contradiction:
Improvestraight path accuracyVSAvoidtravel speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The robot cleaner maintains continuous rotation of both spin-mops during travel, eliminating the sequential activation pattern. Both spin-mops rotate simultaneously and continuously, providing continuous cleaning action while their combined friction forces propel the robot forward in a straight path, thereby maintaining both path accuracy and high travel speed

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables efficient and complete floor cleaning with reduced uncleaned regions, increased travel and cleaning speed, and the ability to perform both wet and dry cleaning effectively, maintaining a conventional intuitive travel motion.

Implementation Method 1

the rotary members are concurrently rotated on a floor surface while portions of the mops fixed to the rotary members are in contact with the floor surface to generate friction forces to move the robot cleaner

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

A robot cleaner may suction foreign matter, such as dust, from the floor or may sweep away foreign matter on the floor while traveling autonomously

Methodology Applied
Scientific EffectMechanical cleaning: Abrasion

Data Source

PatentEP3440981B1Robot cleaner
Publication Date: 2021.04.28 LG ELECTRONICS INC
  • EP3440981B1 patent drawingFigure 1~2
  • EP3440981B1 patent drawingFigure 3~4
  • EP3440981B1 patent drawingFigure 5

AI summary

A robot cleaner includes a cleaning module having a left spin-mop and a right spin-mop configured to contact a floor while rotating in a clockwise direction or in a counterclockwise direction when viewed from above. The robot cleaner also includes a controller that manages the cleaning module such that, when the robot cleaner travels in a zigzag pattern including a first travel, during which the robot cleaner travels straight in a first direction, and a second travel, during which the robot cleaner travels straight in a second direction, which is opposite the first direction, a movement trajectory of the left spin-mop or the right spin-mop during the second travel overlaps a movement trajectory of the left spin-mop and a movement trajectory of the right spin-mop during the first travel.